Microwave Shielding Characteristics of ${\hbox{PMMA/BiFeO}}_{3}$ Composites

BiFe 1-x Sm x O 3 composites with different samarium (Sm) concentration ( x =5-20%) in BFO 3 were fabricated by the solid-state method. Their structure and magnetic property due to the samarium substitution in BFO 3 were analyzed by the X-ray diffractometer and vibration sample magnetometer responses, respectively. The complex permeability (μ = μ'-jμ") and shielding effectiveness (SE) of powder-resin composites consisting of magnetic particles (BiFe 1-x Sm x O 3 ) embedded into a dielectric matrix (PMMA) were studied at the microwave frequencies. The samarium concentration dependence of permeability and SE was measured using the free-space method. We found that the magnetic properties of the Sm-substitute BFO 3 mainly lead to the shielding effect for the PMMA/BiFe 1-x Sm x O 3 composites. In this paper, we demonstrate the gradual change of the shielding effect and permeability of the PMMA/BiFe 1-x Sm x O 3 composites in the microwave range.